1. Field of the Invention
The present invention is directed to a system for creating and using cost zones based on a digital map.
2. Description of the Related Art
The computer has revolutionized the idea of a map from an image statically depicting the location of physical, political, or other features to the digital map, which consists of geographically referenced digital data quantifying a physical, social or economic system. The range of information included in digital maps is unlimited; for example, digital maps could include distances between elements, driving time, lot numbers, tax information, tourist information, etc. Additionally, storing a map as a file on a computer allows for unlimited software applications to manipulate that data. One use that has involved digital maps includes path finding.
One application for digital maps that has not been used effectively is the ability to determine where one can travel within a certain cost limit. Examples of cost include time, distance, tolls paid, ease of turning, quality of scenery, etc. Thus, a traveler may wish to know how far that traveler can drive without paying more than $10 in toll, what restaurants are within a 10 minute drive, or what gas stations are within a one mile walk. In each of these situations, the traveler desires to know where they can travel to within a given cost. The area that they can travel to within that cost is called a "cost zone." In the past, that traveler would look at a traditional map and use the map's key to guess how far they could travel if the cost under consideration was distance. If the cost was time, the traveler would estimate distance and make an educated guess as to time. If the traveler is unfamiliar with the streets on the map, then a guess regarding time of travel would probably not be accurate.
Digital maps in conjunction with path finding systems can be useful for determining cost zones. For example, a digital map can store some or all of the desired costs for the elements in an map. If a user desires to travel to a location, a computer can determine the costs to travel to that location. Such a system is inefficient. If the traveler wants to know all gas stations within one mile, the traveler would have to search a map to find all the gas stations, then run a path finding application once for each such gas station to determine whether that gas station is within one mile.
One attempt at creating cost zones includes using a map already divided into regions unrelated to costs (e.g. zip codes). A point is designated in each region that is used to approximate the entire region. The cost of travel to each of the designated points is determined. Based on those costs, entire regions are included or excluded in the cost zone. Cost zones created by this solution have not proven to be sufficiently accurate.
Therefore, a system is needed that allows a traveler to efficiently and more accurately create and/or use a cost zone.